Rock drill



Patented Elec. 1, 1931 narran STATES PATENT .OFFICE i ELMER G. GARTIN, OECLAREMONT, NEIN` HAMPSHIRE, ASSIGNOR TO SULLIVAN MA- CHINERY COMPANY, A CORPORATION F ,MASSACHUSETTS v noon DRiLn Application filed August 27, 1927. Serial No. 215,960.

My in vention relates to rock drills. An object of the invention is toprovide improved means for supplying cleansing fluid to a hollow drill steel to aid in removing the cuttings from the hole.

`Another object is to provide improved means for supplementing the cleansing fluid supply by conducting a portion of the fluid to the drill steel .from the rear end of the cylinder at about the time it A more specific object is to provide means carried the rifle bar for opening communication between the rear end of the cylinder and the drill steel when the piston is inthe forward part of the cylinder and closing such communication at all other times. Other objects and advantages will, however, subsequently more fully appear.

In the accompanying 4drawings I have` shown for purposes of illustration one form. which my invention may assume in practice.

In these drawings,

F ig. 1 is a central longitudinal section of parts of a typical drilling apparatus having my improved cleansing fluid supply means associated therewith.

Fig. 2 is a view similar to Fig. l showing the moving parts in a different position.

In this illustrative embodiment I have shown my improvements associated with a drilling apparatus of the pressure fluid percussive type comprising` a cylinder lhaving a bore 2 in which a piston 3 is reciprocable, and adapte-d to vactuate a drill steel 5 rotatably supported in a chuck housing 6. The rear end of the cylinder is closed by a head block 7 and this head block, chuck housing and cyl-Y inder may be secured together by any suit-` able retaining means such as side rods 8 .c passing through lugs 9 on the head block, lugs 10 on the cylinder, and a retaining collar 11 surrounding the chuckhousing and abutting against a shoulder 12. i The drill steel may be automatically rotated by the well known type of rotation mechanism employing a ratchet ring 13 secured in the head block, cooperating with a pawl Acarrier 14': and the usual pawls which are not illustrated in detail.l Pro` jecting forwardly from the pawl carrier through a bore l5 in the head block is' a rifle bar 16 having spiral lugs 17 formed thereon and rifle nut.

forcooperating with spiral flutes in a rifle nut 1S in the pistonl 3. Preferably on the rearward stroke of the piston the rifle bar is held from rotation bymeans of the ratchet ring Y and pawl carrier, and the piston is thus rotated by the spirally groo-ved rotation bar This rotation is transmitted through straight longitudinally extending liutes 19 in the striking bar 20, a chuck nut 21 having straight grooves 22 for cooperation with lugs 19, and a rotatable chuck sleeve 23 having lugged engagement with the drill steel 5 in the usual manner (not illustrated) As herein shown, the drilling mechanism is provided with means for supplying a cleansing medium7 such as water, from a connection 24 on the head block 7, through a tube 25 eX- tending longitudinally through the rifle bar and loosely fitting in a bore 26 in the piston 3. This tube extends through the piston and into a bore 27 in the shank of the drill steel.

It has been foundfthat a mixture of gaseous fluid with a liquid produces a more effective cleansing action and accordingly my improved drilling mechanism is provided with means for conducting a portion of the fluidy which is used to actuate the drilling motor to the bore in the drill steel. It is common practice to so designthe longitudinally extending flutes 19 in the striking bar that the same communicate with the forward end ofthe cylinder when the piston is in its rearward position asshown in Fig. 1. This allows a puff of the fluid which is in the cylinder to escape through the flutes 19 linto the chamber 28 surrounding the shank of the drill steel and from this point it readily finds its way past a reduced extension 29 on the tube into the bore of the steel. According to my invention I also provide means whereby this action may be supplemented by a pud of pressure fluid from the rear end of the cylinder when the piston is in the forward part of its stroke. For this purpose the rifie bar 16 has a reduced forward extension 30'which is received in an intermediate bore 31 'during the greater part of the piston stroke, but is of such length that it is removed into the enlarged bore as illustrated in Fig. 2 when the piston is in its forward position,

The valve generally designated 32 is of the four spool differential type having enlarged spools 33 for controlling admission of fluid from the annular space31l to the ends of the cylinder through passages 35k and 36. Motive liuid is supplied to the space 34 through a suitable connection (not shown) by Way of the supply port 37. End spools 38 and 39 control the exhaust of fluid from each end of the cylinder through annular grooves 40 and exhaust ports 4l. rlhe valve is adapted to be automatically thrown from one position to another by suitable piston controlled throw passages communicating with the cylinder at l2 and 43. For a further description of this particular type of fluid distribut-ion system reference may be had to another application Serial No. 215,958 filed by me, of even date herewith, in which application said fluid distribution means is fully disclosed and claimed. It will of course be understood, as far as the present invention is concerned, that any of the generally known types of distribution systems, either valve controlled or valveless, may be employed in the place of the one shown in the drawings.

`rhe operation of my improved fluid cleansing supply means will doubtless be apparent from the above description and drawings, but may be briefly summarized as follow-s. When the piston is in the position shown in Fig. l and during the greater portion of its power stroke the extension 30V on the rifle bar is received within the bore 3l of the piston, thereby preventing passage of motive fluid from the cylinder through the piston. This allows the full force ofthe motive fluid flowing through the inlet passages to act on the piston and more effectively drive the same forwardly in its power stroke. Near the end of the stroke, however, as will be observed in Fig. 2, the extension 30 moves out of the bore 31 and allows pressure fluid in the rear end of the cylinder to escape through the rifle nut 13 around the riiie bar and through the bores 3l and 26 of the piston around the tube 25, and into the bore of the drill steel as will be obvious from the drawings. At this point gaseous fluid commingles with the water or other liquid flowing through the tube 25 and this mixture vis conducted through the hollow drill steel to the bottom of the hole for the purpose of removing the cuttings. It will be clear that if the extension 30 were omitted that motive fiuid would escape around the rifle bar and through the piston during its entire stroke, thereby using an ex cessive amount of live pressure fluid and at the same time reducing the effective pressure on the piston and correspondingly reducing the force of the blow delivered to the drill steel. lieved until near the end of the stroke, the force of the blow will not be materially reduced. It may also be noted that by forming the cleansing fluid supply control as a part ofthe rifie bar a very simple and dependable construction is obtained.

While I have'in this application specifically described one form which my invention may assume in practice, it will be understood that this form of' the same is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

l. In a drilling mechanism, a cylinder, ahollow piston reciprocable therein, a hollow drill steel actuated thereby, means for rotating said piston and steel including a rifle bar extending from the rear end of the cylinder into the piston, and means carried by said rifle bar for controlling communication between the rear end of the cylinder and the drill steel, said means adapted to open said communication when the piston is in the forward part of its stroke,such opening being dependent solely on the position of the piston.

2. In a drilling mechanism, a cylinder, a hollow piston reciprocable therein, a hollow drill steel actuated thereby, means for rotating said piston and steel including a rifle bar extending from the rear end of the cylinder into the piston, and a rifle nut in said piston cooperating therewith in a manner to admit free passage of fluid therethrough, and means integral with said rifle bar for controlling communication between the rear end of the cylinder and the drill steel, said means adapted to admit pressure fluid from the rear end of the cylinder to the hollow drill steel when the piston isV in the forward part of its stroke, such admission being controlled solely by the position of said piston.

. 3. In a drilling mechanism, a cylinder, a hollow piston reciprocable therein, a hollow drill steel actuated thereby,rmeans for rotating said piston and steel including a rifle bar extending from the rear end of the cylinder into the piston, and a rifle nut in said piston cooperating therewith, said rifle bar having a portion attached thereto adapted to fit closelyin a bore in said piston, and means permitting the intermittent withdrawal of However, if this pressure is not resaid portion from said bore to allow cleansing fluid to escape from the rear end of the cylinder through the piston when the latter is in the forward part of its stroke.

4. In a drilling mechanism, a cylinder, a hollow piston reciprocable therein having a plurality of bores of different sizes, rotation mechanism including a rifle bar extending from the rear end of the cylinder into one of said bores, said rifle bar having a reduced extension attached thereto and projecting forwardly therefrom and slidably fitting in another of said bores, and means permitting the intermittent withdrawal of said extension from its bore to allow cleansing fluid to escape from the rear end of the cylinder through the piston when the latter is in the forward part of its stroke.

5. In a drilling` mechanism, a cylinder, a hollow piston reciprocable therein, rotation mechanism including a rotation element operatively connected to said piston, means for supplying cleansing iiuid to a hollow drill steel comprising tube means extending through said piston for continuously conducting cleansing fluid, and means for suppleinenting said cleansing fluid comprising a member separate from said tube means and attached to said rotation element, said member slidably fitting in a bore of said piston and adapted to be withdrawn therefrom when the piston is in the forward part of its stroke.

6. In a drilling mechanism, a cylinder, aI hollow piston reciprocable therein, rotation mechanism including a rifle bar extending into the rear end of said cylinder, means for supplying cleansing fluid to a hollow drill steel comprising a tube extending through said piston for continuously conducting cleansing fluid, said piston beingprovided with a reduced bore loosely fitting said tube, a large bore for cooperation with said rifle bar and an intermediate bore, means attached to said rifle bar for closing said intermediate bore, and means permitting intermittent withdrawal of said closing means to supply cleansing fluid from the rear end of the cylinder to the drill steel.

7. In a drilling mechanism, a cylinder, a hollow piston reciprocable therein, a tube extending through said piston for continuously conducting a cleansing medium, rotation mechanism including a rifle bar projecting from the rear end of the cylinder into sai piston, and means carried by said rifie bar and surrounding said tube for controlling communication between the rear end of the cylinder and drill steel to allow supplemental supply of cleansing fiuid to fiow through the piston when the latter is in the forward part of the stroke, said supplemental supply being controlled solely by the position of said pist-on.

8. In a drilling mechanism, a cylinder, a hollow piston reciprocable therein having a plurality of central bores of different diameters, a tube extending through said piston and loosely fitting in the smaller of said bores for conducting a continuous supply of cleansing fluid to the drill steel, rotation mechanism including a rifle bar extending from the rear end of the cylinder into the larger of said bores, a rifle nut in said piston cooperating with said rifie bar in a manner to permit passage of fluid into said enlarged bore, a reduced projecting portion on said rifle bar surrounding said tube and slidablyfitting in an intermediate bore when the piston is in the rearward portion of the cylinder and adapted to withdraw from the same into said larger bore when the piston is in the forward portion of the cylinder to allow cleansing fluid to escape from the cylinder through the piston.

9. In a drilling mechanism, a cylinder, a piston, a. chuck, and means whereby reciprocation of said piston effects chuck rotation including a member carried by said cylinder and having a reduced portion having splined connection with said piston, said piston having a bore therethrough and said member having a portion cooperating with` said bore to effect intermittent opening and closing of the latter.

10. In a drilling mechanism, a cylinder, a 

